DETERMINATION OF ANIONIC SURFACTANT ADSORPTION CAPACITY OF EXPANDED PERLITE FROM AQUEOUS SOLUTION

Abstract

Surfactants are major constituents of detergent so that it is frequently present in domestic and industrial wastewater. The surfactants cause foams in rivers and surface waters, thereby reducing the oxygen penetration in water and posing environmental risks to aquatic organisms. They need to be removed from wastewater to avoid environmental damages. Adsorption is a conventional method for surfactant removal from the water environment. Perlite is an amorphous volcanic glass that has relatively high water content and is typically formed through the hydration of obsidian. It occurs naturally and has the unusual property of greatly expanding when heated sufficiently. Expended perlite have been used as an economical adsorbent in adsorption process due to its low cost and large surface area. The aim of this study was to determine an anionic surfactant adsorption capacity of expended perlite from aqueous solution. For these purposes, linear alkyl benzene sulphonic acid (LABSA) was used as a surfactant and the effects of pH, temperature, concentration of LABSA, amount of adsorbent and contact time on adsorption capacity of expended perlite were investigated. The adsorption kinetic was found to follow the pseudo second order kinetic model. The equilibrium adsorption data were well described by the Freundlich isotherm model. Finally, the thermodynamic parameters including, the change of Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees) and entropy (Delta S degrees) of adsorption were calculated. The results showed that the adsorption of LABSA on expended perlite was feasible, spontaneous and exothermic at 15-45 degrees C.